package com.sakura.util;

import java.security.MessageDigest;
import java.util.Arrays;

public class CheckUtil {

	private static final String TOKEN = "sakura";
	
	public static boolean checkSignature(String signature, String timestamp, String nonce){
		String[] arr = new String[]{TOKEN, timestamp, nonce};
		//排序
		Arrays.sort(arr);
		//生成字符转
		StringBuffer content = new StringBuffer();
		for (String string : arr) {
			content.append(string);
		}
		//加密
		String sha1 = getSha1(content.toString());
		//比较
		return sha1.equals(signature);
	}
	
	/**
	 * SHA1加密字符串
	 * @param str
	 * @return
	 */
	public static String getSha1(String str){
        if(str==null||str.length()==0){
            return null;
        }
        char hexDigits[] = {'0','1','2','3','4','5','6','7','8','9',
                'a','b','c','d','e','f'};
        try {
            MessageDigest mdTemp = MessageDigest.getInstance("SHA1");
            mdTemp.update(str.getBytes("UTF-8"));

            byte[] md = mdTemp.digest();
            int j = md.length;
            char buf[] = new char[j*2];
            int k = 0;
            for (int i = 0; i < j; i++) {
                byte byte0 = md[i];
                buf[k++] = hexDigits[byte0 >>> 4 & 0xf];
                buf[k++] = hexDigits[byte0 & 0xf];      
            }
            return new String(buf);
        } catch (Exception e) {
            return null;
        }
    }
}
